Sadly, some agents don't earn a real commission, and may only make $25 per booking. Especially those with big box agencies or those who are entirely focused on offering the lowest price. Post booking services in these cases will be minimal if anything at all.
Then there are the lazy agents, who although they may be earning the standard commission, are only interested in booking your reservations, and not properly servicing it.
There are plenty of good agents out there, but CC rules prohibit sharing such information.